On the sensitization of the Pr3+ Photon Cascade Emission by the 4fn−15d1 states of the Tm3+ and Nd3+ ions in YF3

• Sensitization of YF3:Pr3+ Photon Cascade Emission by Tm3+ and Nd3+ is examined.
• Sensitization of Pr3+1S0 → 1I6 emission transition is observed.
• Tm3+ and Nd3+ additions quench the emission from the Pr3+3P0 state.
• Energy transfer between Tm3+ and Pr3+ is characterized.

The sensitization of the Pr3+ Photon Cascade Emission by the 4fn−15d1 states of the Tm3+ and Nd3+ ions in YF3 has been studied at room temperature and over a wide range of sensitizer concentrations. Strong sensitization of the Pr3+1S0 → 1I6 emission transition is produced when exciting into the interconfigurational transition (4fn → 4fn−15d1) of the sensitizer ions (λex = 147 nm). However, the luminescence efficiency of the Pr3+3P0 state decreases with increasing proportions of the Tm3+ and Nd3+ ions because of the nonradative energy transfer that occurs between the 4fn states of Tm3+/Nd3+ ions and the Pr3+3PJ state. The various energy transfer channels that are operative between the 4f2 and 4f12 states of the Pr3+ and Tm3+ ions are identified and characterized. It is noteworthy that the addition of Tm3+ and Nd3+ ions has a detrimental effect on the luminescence efficiency of the Pr3+1S0 state when exciting directly into the Pr3+ ion (λex = 185 nm). This is a surprising result since there is an absence of energy matching between the Tm3+ 4f12/4f115d1 and the Pr3+1S0 states and because efficient Tm3+ → Pr3+ energy transfer is observed for λex = 147 nm. The possible reasons for this are discussed.